diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/arm/mmap.S')
-rw-r--r-- | sysdeps/unix/sysv/linux/arm/mmap.S | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/arm/mmap.S b/sysdeps/unix/sysv/linux/arm/mmap.S new file mode 100644 index 0000000000..cf6f253378 --- /dev/null +++ b/sysdeps/unix/sysv/linux/arm/mmap.S @@ -0,0 +1,92 @@ +/* Copyright (C) 1998, 2000, 2003 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <sysdep.h> +#include <kernel-features.h> + +#define EINVAL 22 + + .text + +ENTRY (__mmap) +# ifdef __ASSUME_MMAP2_SYSCALL + /* This code is actually a couple of cycles slower than the + sys_mmap version below, so it might seem like a loss. But the + code path inside the kernel is sufficiently much shorter to + make it a net gain to use mmap2 when it's known to be + available. */ + + /* shuffle args */ + str r5, [sp, #-4]! + ldr r5, [sp, #8] + str r4, [sp, #-4]! + ldr r4, [sp, #8] + + /* convert offset to pages */ + movs ip, r5, lsl #20 + bne .Linval + mov r5, r5, lsr #12 + + /* do the syscall */ + swi SYS_ify (mmap2) + + /* restore registers */ +2: + ldr r4, [sp], #4 + ldr r5, [sp], #4 + + cmn r0, $4096 + RETINSTR(cc, lr) + b PLTJMP(syscall_error) + +.Linval: + mov r0, #-EINVAL + b 2b +# else + /* Because we can only get five args through the syscall interface, and + mmap() takes six, we need to build a parameter block and pass its + address instead. The 386 port does a similar trick. */ + + /* This code previously moved sp into ip and stored the args using + stmdb ip!, {a1-a4}. It did not modify sp, so the stack never had + to be restored after the syscall completed. It saved an + instruction and meant no stack cleanup work was required. + + This will not work in the case of a mmap call being interrupted + by a signal. If the signal handler uses any stack the arguments + to mmap will be trashed. The results of a restart of mmap are + then unpredictable. */ + + /* store args on the stack */ + stmdb sp!, {a1-a4} + + /* do the syscall */ + mov a1, sp + swi SYS_ify (mmap) + + /* pop args off the stack. */ + add sp, sp, #16 + + cmn r0, $4096 + RETINSTR(cc, lr) + b PLTJMP(syscall_error); +#endif + +PSEUDO_END (__mmap) + +weak_alias (__mmap, mmap) |